Hf deasphalting for hydrocracking feed preparation



Ot. 25, 1966 H. G. GODET ETAL HF DEASPHALTING FOR HYDROCRACKING FEEDPREPARATION Filed May 6, 1963 United States Patent O HF DEASPHALTING FORHYDROCRACKING FEED PREPARATION Howard G. Codet, Westfield, and John W.Herrmann, Mountainside, NJ., assignors to Esso Research and EngineeringCompany, a corporation of Delaware Filed May 6, 1963, Ser. No. 278,086 8Claims. (Cl. 208-62) The present invention relates to the conversion ofhydrocarbons and more particularly t-o a highly integrated process inwhich hydrogen fluoride deasphalting and demetalization of the higherboiling hydrocarbons is utilized t-o obtain treated hydrocarbons fromwhich a hydrocracking feed, a reformer feed and a Ithermal crackingfeed, which is used to make hydrogen and a high value coke, areobtained.

It has long been recognized that hydrocarbon fractions, such as crudepetroleum oil, atmospheric residuum or vacuum bottoms normally containiron, nickel, vanadium and other metallic contaminants which have anadverse effect upon various catalysts employed in the petroleumprocessing operations and upon combustion equipment in which suchpetroleum fractions are burned as fuels. Furthermore, these metalliccontaminants or substances poison catalysts used in operations such ashydroforming and hydrocracking. In the high boiling fraction or residualtype fuels such contaminants attack the refractories used to lineboilers and combustion chambers, cause clogging and the buildup ofdeposits upon boiler tubes and severely corrode metallic surfaces withwhich they come into contact.

Further well-known difficulties have been caused by the presence ofasphaltenes and asphaltic substances which con-tain compounds of sulfurand nitrogen. Gasoline must be relatively sulfur free in order to makeit compatible with lead. Motor fuels containing sulfur as mercaptans areundesirable because of odor and gum formation characteristics. Sulfur isparticularly objectionable in fuel oils because it burns to form SO2which is a highly corrosive and foul-smelling compound. As for nitrogen,this element, even in relatively slight amounts, can have disastrouseffects on catalytic activity within the refinery process, particularlywith cracking catalysts. In addition the asphaltenes and asphalticsubstances themselves yield large quantities of coke upon cracking, asevidenced by their high Conradson carbon content.

In prior processes, a separate hydrofning step was needed beforereforming or hydrocracking to remove nitrogen, sulfur and othercontaminating materials. Hydrofining 4was also needed -to improve odor,appearance and stability of various products. However, although theresults of this process are quite satisfactory, there .is considerableexpense involved. It is, therefore, desirable to find a method in whichthis step may be eliminated and yet produce feed stocks which will haveall desired characteristics.

It should also be noted that an inferior grade coke is often a byproduct of refinery operations. This coke with its high metals andcontaminant content must be either sold at a low price for use as fuelor further processed, at considerable expense, to make it acceptable forother uses such as metallurgical or electrode coke.

These problems and various others are successfully solved by the presentinvention. According to this invention, an oil such as a preflashedcrude, atmospheric residuum or vacuum bottoms (after being diluted withpropane) is treated with hydrogen fluoride (HF) in either aqueous oranhydrous form, thereby precipitating a solidmetals complex and forminga raliinate and an extract. The Conradson carbon, aromatics, sulfur andnitrogen are 3,281,350 Patented Oct. 25, 1966 concentrated in theextract fraction. This extract amounts to about 15-25% of the oil feed.The extract, after removal of the HF, is made substantially metal-freeby filtering out the precipitated solid-metals complex. After this, thefiltered extract is -ther-mally cracked to produce hydrogen and apremium-value, metals free coke. The hydrogen is passed into ahydrocracker.

The raffinate, or petroleum fraction which has been separated from theextract, is stripped of HF and filtered and then directed to afractionating tower. Here the raffinate is fractionated and a pluralityof streams recovered. The lightest fraction is sent directly to ahydroformer. The middle fraction is withdrawn from the system and may beutilized as diesel fuel, jet fuel or heating oil component. The bottomfraction is passed into the hydrocracker int-o w-hich the hydrogen fromthe thermal cracker was passed. This hydrogen, along with the hydrogenproduced in the hydroformer operation, provide sufficient hydrogen forthe hydrocracking operation. After -hydrocracking, the hydrocrackednaphtha is divided into two parts; a heavier part going to thehydroformer, along with the lightest virgin cut from the fractionatingtower, and a lighter fraction which is used directly as a gasolineblending component. The hydroformed naphtha is recovered and provides ahighly desirable motor fuel. It should be noted that no hydrofiningoperation is needed to remove impurities from either the hydrocracker orreformer feeds.

The figure diagrammatically represents one form of apparatus adapted topractice the present invention.

In the drawing, the reference character 10 designates a line throughwhich a crude petroleum oil to be treated is passed into preashingvessel 11. A lighter fraction, boiling below about 200 F., is drawn offoverhead through line 12; this fraction usually represents less than 10%of the entire oil feed. Usually over 90% of the crude oil feed, boilingabove about 200 F., is removed from vessel 11 through line 13 and ispassed into a combined deasphalting and demetalization or extractionzone or tower 14. An aqueous solution of or anhydrous HF in the amountof 0.1 to 1.0 weight of HF per Weight of oil is directed into the zone`through line'15. In this extraction zone 14 the crude oil and HF acidare contacted by mixing or by agitation for a period of 1-90 minutes ata temperature of 200-350 F. in order `to convert the metals to aninsoluble inorganic fluoride complex. At the same time, the HF-oilmixture separates into a raffinate phase and an extract phase.

A bottom stream of extract phase from extraction zone 14 amounting tol0-20% of the total crude and containing most of the HF, feed Conradsoncarbon components, polynuclear aromatic, nitrogen and sulfur compoundsand the precipitated metals complex is withdrawn through line 16 to astripper tower 17 where HF is recovered and recycled back to theextraction zone 14 through line 18. Stripping gas, such as butane, maybe introduced into `stripper 17 through line 17. Stripper 17 ismaintained at a temperature of 200 to 300 F. The HF free extract is fedfrom the stripper zone 17 through line 18' to a filter 19 and the solidmetals complex removed through line 20. This complex is only a fractionof a percent of the total crude. The filter may be any conventionalfilter such as `a simple sand filter, a rotary filter, or a Dorrsettler. Subsequent to filtration, the extract from which thesolidrnetals complex has been removed is introduced into thermalcracking or high temperature coking zone 21 to produce coke andhydrogen.

This thermal cracking zone consists of a reactor containing a fiuidizedbed of coke and operating at about 1700-2600 F. and 0-100 p.s.i.g. toproduce hydrogen and coke. Temperature is maintained by burning naturalgas in a transfer line burner through which part of the coke iscirculated, by electrical resistance heating within.

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o the Huid bed itself or other suitable means of heat supply. In thismanner, a virtually metal-free coke is produced and withdrawn throughline V22. Simultaneously, hydrogen is recovered from the thermal cracker21 overhead and passed to hydrocracker 23 through line 24.

The overhead stream from demetalization and deasphalting zone 14includes raffinate amounting to 80-90% of the crude as well as some HFand solid metals complex. The stream is withdrawn through line 25 andpassed to stripper tower 26. Stripping tower 26 is maintained at atemperature of 200 to 300 F. Stripping gas may be introduced into thetower through line 26 is desired.

In stripper tower 26 HF is taken overhead through line 27 and passedinto line 18. The HF passes through line 18 into deasphalting zone 14.Deasphalted oil is removed as a bottoms stream from stripper 26 throughline 28 to filter 29 where the remaining solid metals complex isremoved. The demetalized raffinate is passed through line 30 intoatmospheric tower 31 from whence three streams are withdrawn.

A light fraction, boiling between about ZOO-375 F. and consisting ofapproximately -15% of the volume of the crude oil feed is drawn offthrough line 32 and passed to hydroformer 33. An intermediate fractionboiling between about 375 and 430 F. is drawn off through line 34 andmay be utilized for any suitable purpose such as heating oil, dieselfuel or jet fuel; this would consist of approximately 0-10% of thevolume of the crude oil feed. Finally, a bottoms fraction consisting of60-70% of the crude oil feed, and boiling above 430 F., is removedthrough line 35 and sent directly to hydrocracker 23. The hydrocrackerfeed is heated in any conventional manner to about 500 to 750 F. bymeans not shown.

Hydrocracker 23 may be of the fluid catalyst variety but it is preferredto use a fixed bed catalyst hydrocracking zone. It is preferred to use abifunctional sieve-based catalyst such as palladium on a crystallinezeolitic metal alumino-silicate molecular sieve having uniform poreopenings between about 6 and 15 A. units or palladium on a decationizedcrystalline zeolitic metal alumino-silicate molecular sieve havinguniform pore openings between about 6 and 15 A. The molecular sieve isfurther characterized in that it contains no more than about sodiumcalculated as NaZO, preferably between about 0.5 and 8.5%

The molecular sieves are crystalline zeolitic aluminosilicates that arecharacterized by having pores of a uniform diameter. They may be eithera natural zeolite such as Faujasite or they may be synthetic zeolitessuch as the 13X or 13Y molecular sieves. The ammonium sieve may beimpregnated with palladium by treatment with a solution of palladiumchloride. The palladium impregnated ammonium sieve is converted to theactive catalyst by heating to a temperature in the range of 600-1000 F.to drive olf the ammonia and reduce the palladium to a zero valencestate. The amount of the palladium in the catalyst is between 0.01 and5.0 wt. percent.

Other bifunctional catalysts may be used which may consist of aconventional cracking component plus a minor proportion of a heavy metal-oxide or sulde which is effective in the promotion of hydrogenationreactions. Such catalysts may comprise for example between about 1% and10% by weight of the oxides or sulfides of the transitional metals,particularly those of Groups VB, VIB, VIIB :and VIII, or mixturesthereof. Particularly desirable components consist of the oxides orsulfides of chromium, molybdenum, tungsten, iron, cobalt, nickel, or themetals platinum, or palladium. The carrier on which these materials aredeposited may consist for example of synthetic coprecipitatedsilica-alumina, silica-zirconia, silica-titania,silica-titania-zirconia, silica-magnesia, and the like. Acid-activatedmontmorillonite clays may also be employed. Any of these carriers may befurther activated by the incorporation of small amounts of acidicmaterials such as uorine or chlorine.

The alternate catalysts for the hydrocracking reaction may consist of acoprecipitated base composed of l0 to 65% silica, 15 to 65 titania, and15 to 65 zirconia, on which is deposited as by impregnation orcoprecipitation a minor amount, from about 0.5% to about 7%, of apromoter, e.g. an oxide of chromium, molybdenum, tungsten, cobalt,nickel, or any combination thereof. Alternatively, even smallerproportions, between about 0.05% and 1.0% of the metals platinum orpalladium may be employed. The oxides and sulfides or other transitionalmetals may also be used, but to less advantage than the foregoing.

Operative conditions in the hydrocarcking zone depend upon feedstockquality and the degree of conversion required. Hydrocrackingtemperatures (average bed) may -suitably range between about 500 and1000 F., and preferably lbetween about 550 and 800 F.

Pressures in the hydrocracking zone may range between about 500 an-d3,000 p.s.i.g., and preferably between about 800 and 2,500 p.s.i.g. Theliquid hourly space velocity may range between about 0.5 and 4 volumesof liquid feed per volume of catalyst per hour.

Since the process is exothermic, provision must be made for removingheat from the system. The preferred method is to inject streams of coolhydrogen-rich gas at intermediate points along the length of the lfixedbed of catalyst. In addition to this cooling gas and the makeup hydrogenwhich is consumed in the process, a stream of hydrogen-rich gasamounting to G-15,000 s.c.f./b. of feed, and preferably -between about2,000 and 10,000 s.c.f./b. of feed is injected at the inlet to thereactor.

Conversion of feed to lighter material is high and unconverted materialmay be separated from product and recycled to the reactor. Hydrogenconsumption depends on feedstock quality and degree iof conversion. Fortypical feeds at total conversion to gasoline, hydrogen consumptionranges between 1600 and 2500 s.c.f./b. feed.

There is virtually no coke make in the process and, therefore, catalystregeneration is needed very seldom, if ever.

After the hydrocracking is complete, the hydrocracked product is removedand passed through line 23 into fractionator 24. Here the hydrocrackedproduct is divided into a .plurality of streams. A C4- fraction isremoved through line 36 and sent to light ends recovery. A C5/180fraction is removed through line 37 and goes directly to motor gasoline.A hydrocracked naphtha boiling between ISO-430 F., amounting to between50 and 60% of the crude oil feed, is withdrawn through line 38 and isadmixed with the 20G-375 F. fraction which was withdrawn through line 32from tower 31. A heavier 430+ fraction is recovered through line 39 andrecycled to hydrocracker 23.

The combined `streams from lines 32 and 38 are passed through line 40into hydi'oformer 33. Within hydroformer 33 the hydrocarbons aretransformed from low grade fuels into high octane motor fuels.Hydroformer 33 may be either of two types, semiregenerative which, asthe name connotes, would require relatively infrequent catalyticregeneration, or cyclic hydroforming which includes frequentregeneration.

The hydroforming zone 33 preferably contains a fixed bed of catalystemploying a platinum on alumina catalyst. Turning first to thesemiregenerative form, the catalyst may contain between about 0.01 and5.0 wt. percent of platinum on alumina containing between about 0.0 and5.0 wt. percent of silica. The pressure in zone 33 is maintained at400-750 p.s.i.g. and preferably 400-500 p.s.i.g. The inlet temperatureis maintained at 925-1000 F. The recycle gas rate which is primarilyhydrogen is maintained within a range of Z500-10,000 s.c.f./b. of oilfeed. Catalyst requirement is based` on a feed rate of 1.5 to 2.5 poundsof feed per hour per pound of catalyst. Lower temperatures are yused atthe start of the operation and the temperature is increased accordinglyas coke deposits form on the catalyst and serve to deactivate it.

The cyclic hydroformer is similar to the semi-regenerative one, exceptthat it does provide for an extra reactor so that one reactor can beregenerated without a stoppage of operations. The hydroformate andhydrogen are passed along line 41 to products recovery zone 42. Thereforming process also makes hydrogen as a by-prod'uct and, as mentionedearlier, part of the hydrogen recycle representing the net hydrogen makeis passed through line 43 and together with the hydrogen coming from thethermal cracker 21 is passed through line 24 to hydrocracker 23.

A high octane reformate is recovered through line 44 which represents60-75% of the crude introduced by means of line 10.

Bottoms are removed throu-gh line 42'.

It is readily seen by one skilled in the art that thepreviously-described HF treating process may be utilized for anatmospheric or vacuum bottoms, although the latter may require theaddition of a -suitable diluent such as propane or butane to increaseease of handling.

Typical data for deasphalting and demetalization of heavy oils areindicated in the following table:

6 subjected to a temperature of 2200 F. and a pressure of 50 p.s.i.g.for a period of 10 seconds or less. A virtually metal-free premiumvalued coke is produced and withdrawn from zone 21 through line 22; thecoke amounts to about 600 t./d.

Simultaneously with the coke production, 29.7 mm. s.c.f./d. of hydrogenare manufactured. This hydrogen is di-rected to hydrocracker 23 throughline 24.

The remaining 25,900 barrels of oil which comprise the railinate fromtower 14 are directed overhead through line to stripper 26. It should benoted that a small amount of HF is included as well as about 10% of thesolid metals complex. The HF is removed from the stripper 26 and throughline 27 and passed into line 18 from whence it is passed to deasphaltingtower 14. The raflnate with included solid metals complex is withdrawnthrough line 28. It is passed through sand lter 29, the solid and metalsare removed. The ralinate is then passed through line into atmospherictower 31. Here the raffinate is fractionated at atmospheric pressure.About 3200 barrels of oil boiling between 200-375 F. are drawn offthrough line 32 and sent to hydroformer Table I Feed 250L1 F. -i-CrudeAtm. Resid. 600 Vae. Resid. 950

HF Deasphalting Conditions:

HF, Wt. per Wt. Oil 0. 5 1.0 0. 5 Butane Diluent Vol. per Vol. Oil FeedNone None 6 Extraction Temperature, F 100 200 200 Feed Rainate FeedRarinate Feed Raiinate Oil Yield:

Wt. percent on Feed 100 80 100 74 100 73 Vol. percent on Feed 100 82 10076 100 76, 5 Inspections:

Gravity, API 28. 6 32A 0 19. 5 23.7 1i. o 19. 2 Conradson Carbon, Wt 2.4 0. 6 5. 5 1. 8 15. 0 4. 6 Sulfur, Wt. pcrcent 1. 4 0. 64 2. 2 1.0 3. 30.9 Nitrogen, Wt percen 0.12 0.01 0.24 0,04 0,43 0 15 N1clrel,p.p.m 50.5 12 1.0 25 0.5 Vanadium, p.p.m 8 0. 0 24 0 39 0 Thus the foregoingtable shows that the raffinate is 33. About 1300 barrels are withdrawnthrough line 34 greatly improved over the eed in concentrations ofcontaminants such as Conradson carbon, sulfur, nitrogen, nickel andvanadium.

In addition to -this improved `feed for hydrocracking, a virtuallymetal-free coke is obtained from thermally cracking the iilteredextract. Furthermore, no hydroning step is needed for either the feedwhich is hydrolined or the feed which is hydrocracked.

In a specific example, about 30,000 barrels of crude petroleum oil arefractionated or preashed in tower 11. About 2100 barrels of hydrocarbonoil boiling -below 200 F. are removed through line 12. The remainder ofthe oil is withdrawn -from the bottom of tower 11 and passed throughline 13 into demetalization and deasphalting zone 14. About 12,000barrels `a day of anhydrous hydrogen fluoride (HF) are added to zone 14through line 15. HF and oil are contacted at about 300 F. for about 10minutes in an extraction tower where the metal contaminants areconverted to insoluble, inorganic fluorides amounting to less than l wt.percent of the freed. At the same time, the HF-oil mixture separatesinto a rafnate and an extract fraction. The extract stream containing4100 b./d. oil, also contains most of the sulfur, nitrogen and Conradsoncarbon containing compounds as Well as the HF and metals complex. Thisis drawn off the bottom of the tower 14 through line 16 to a strippertower 17, where HF is lrecoVe-red and recycled back to the deasphaltingzone 14 through line 18. The HF-free extract is -fed from the strippertower 17 to a sand lter 19 through line 18. The solid metals complex isremoved through line 20. The iiltered extract is removed from the lterthrough line 19 and introduced into thermal cracking unit 21. Thermalcracking unit 21 is of the fluidized bed variety. Here the extract isand used as heating oil. This fraction boils between 375-430 F. Thebottoms fractions, boiling above 430 F and comprising about 19,300barrels, is passed through line 35 to hyd-rocracker 23. The hydrocrackeris of the fixed bed variety and is substantially similar in all details,including catalyst, to the one described previously. The catalystconsists of palladium on la. decationized crystalline zeolitic metalalurnino-silicate molecular sieve having uniform pore openings of about13 A. The molecular sieve contains about 6% sodium calculated as NaZO.The hydrocracking is carried out at a temperature of about 650 F. and a.pressure of about 1500 p.s.i.g. Hydrogen in the amount of 45.6 mm.s.c.f./d. is needed.

The hydrocracked product amounting to about 21,300 barrels per day isremoved through line 23' and passed into fractionator 24. About 16,000barrels of 180-430 F. naphtha per day are Withdrawn through line 38, andtogether with the 3200 barrels per day from line 32 are passed tohydroformer 33. About 5300 barrels per day of C5/ 180 naphtha arewithdrawn through line 37 and utilized directly as a gasoline. About6.75 mm. s.c.f. of C4- components are withdrawn through line 36 anddirected to light ends recovery.

Hydroformer 33 is of the cyclic variety. It is operated at a pressure of250 p.s.i.g. and has a reactor temperature of 975 F. The recycle gasrate is 5000 s.c.f./b. and the catalyst requirement is based on 3 poundsof feed/ hour/pound of catalyst. About 15.9 mm. s.c.f./d. of hydrogenare channeled from the hydroformer 33 into products recovery zone 42 andthen through lines 43 and 24 into hydrocracker 23. About 16,700 barrelsper day of high grade gasoline are recovered through line 44. Thisgasoline has an octane number of about 98 Research, clear.

In the specific example given above, the thermal cracking step and thehydroformer produce all the hydrogen needed for the hydrocracker andhydroformer and no external hydrogen is added.

A conventional refining scheme to produce the required quantity andquality of products would include coking of atmospheric residuum toconvert it to lighter products and help to prepare it for 4furtherprocessing by partial removal of Conradson carbon, sulfur, and nitrogen.The conventional refining scheme operates as follows: Preflashed crudeis -fed to an atmospheric pipestill Ifor fractionation into severalstreams. The heaviest portion, 750 F.-{ atmospheric bottoms, is fed to acoker where it is converted into naphtha, gas oil, coke, and fuel gas.The coke from this unit contains a high proportion of the metalcontaminants from the crude oil. This makes it a low valued product thatmust be burned as fuel or processed at considerable expense to make itsuitable for more attractive outlets such as electrode coke. The cokergas oil boiling 4between about 430 F. and 850 F. is combined with thevirgin gas oil boiling between about 430 F. and 750 F. from theatmospheric tower and the combination is sent to a two-stagehydrocracking unit. The first stage of this hydrocracking unit isprimarily a hydrofiner to remove nitrogen from the feed and make itsatisfactory for the second stage where the major part of thehydrocracking takes place.

The heavy naphtha product from the hydrocracker boiling between about180 F. and 430 F. is combined with virgin naphtha from the atmospherictower and is sent to a naphtha reformer. At least the virgin naphthaportion of this feed must first be hydrofined to remove sulfur and thusmake it suitable for reforming. Hydrogen produced in -the reformer isused to meet part of the hydrocracker hydrogen requirements. To completethe hydrogen requirements, methane is steam reformed in a conventionalhydrogen manufacturing unit.

The gasoline from this refinery is made up of light naphtha from thehydrocracker, reformer product, coker naphtha, butane, and suitableadditives.

The HF deasphalting scheme, which is the subject of the presentinvention, has a number of significant economic advantages over theconventional refinery described above. These can be illustrated mosteasily'by referring to the attached Table 2 which represents operationof a 30,000 b./d. plant.

Although both refineries require equal quantities of crude to makeessentially equal quantities of desired products, the improved case ofthe present invention saves 15,000,000 s.c.f./d. of methane needed inthe conventional case for hydrogen manufacture. Also, because of thebetter quality of the naphtha components in the improved case, much lesstetraethyl lead is needed to make the same quality finished gasoline ineach case. This better naphtha quality results from the absence of lowgrade coker naphtha.

With -regard :to equipment requirements, the improved refinery requiresno conventional coker, no hydrocracker feed hydrofining unit, noreformer feed hydrofiner, and a smaller atmospheric tower than theconventional case. These result in much greater savings than the cost ofthe Irequired deasphalting unit.

Although both refineries make `about the same quantity of gasoline,by-products from the improved case are significantly more valuable. Thisis especially true of the coke yield, which is only worth fuel value inthe con- -ventional case because it is highly contaminated withundesirable metals. On the other hand, improved refinery coke product ofthe present invention is virtually metals free and therefore commands apremium price as electrode coke or for other specialty uses. Inaddition, there is a higher yield of this valuable coke since none of itneeds to be burned for fuel. The improved refinery also makes lesslow-value fuel gas and more high-value propane and butanes, which can beused for such things as liquefied petroleum gas and gasoline components.For these reasons, the improved processing scheme represents a much moreeconomically attractive refinery.

Atmospheric tower Fluid Coker H/F Deasphalting Unit Hydrofiner forreformer feed.

Hydrofmer for hydrocracker feed.- Products:

a. C4, net, b./d Fuel value Coke, t, Premium value coke, Finished Mogas,b./d

1 To make constant quality motor gasoline pool.

Table 2 illustrates some of the advantages of the instant case. Itshould be noted that considerably less TEL is needed to make a gasolineof instant quality. Additionally, as would be expected the need formethane as a source of hydrogen is eliminated. Considerably more coke isproduced and it is of a premium quality.

What is claimed is:

1. In -a process for the preparation of a hydrocracking feed andproduction of a high value coke, the steps which comprise preiiashing acrude oil, thereby obtaining a lighter fraction boiling below about 200F. and a heavier fraction boiling above about 200 F., recovering thesaid lighter fraction, passing said heavier fraction into a deasphaltingand demetalization zone, passing HF into said zone for contacting saidheavier fraction and in a sufficient amount to precipitate substantiallyall metals from said heavier fraction and to form an extract phase whichamounts to about l0-20% of said crude oil feed in which are concentratedthe compounds containing sulfur, nitrogen and Conradson carbon and aseparate raffinate phase which amounts to about -90% of said crude oilfeed, said precipitate being collected primarily in said extract phase,separating said extract phase and said raffinate phase, removing saidextract phase from the said de- ,asphalting zone, filtering said extractphase to remove said precipitate containing heavy metal contaminants,passing the filtered extract phase into a high temperature thermalcracking zone, cracking the said metal-free extract substantiallycompletely to metal-free coke and hydrogen, recovering said coke as apremium llow meta-ls coke, passing at least part of the said hydrogeninto a vhydrocracking zone, fractionating said rafiinate phase intothree streams, including (l) a lighter boiling stream Iwhich is passedwithout hydrofining to a hydroforming zone where it is hydroformed inthe presence of hydrogen gas, recycling part of said hydrogen gas fromsaid hydroforming zone to said hydrocracking zone, (2) an intermediatestream which is removed from the system as product, and (3) -a bottomsstream which is passed without hydrofining into -the said hydrocrackingzone containing a catalyst comprising palladium on an aluminum silicatemolecular sieve where it is hydrocracked in the presence of the 4recyclehydrogen from the said hydroforming zone and hydrogen from said thermalcracking step, recovering a low `boiling hydrocrackate naphtha-fractionwhich is re- `moved from the system and a higher boiling hydrocrackatenaphtha fraction which is passed to the said hydroforming zone, andrecovering ya high quality fuel from the said hydroforming zone.

2. The process of claim ll Where the said HF and said heavier fractionare contacted for a period of 1 to 60 minutes.

3. The proces-s of claim 1 Where the said lter is a sand filter.

4. The process of claim 1 where the said HF is an aqueous solution.

5. The process of claim 1 where the said three streams into which theranate is fractionated are a ZOO/375 F. lighter fraction, a EWS/430 F.middle fraction and a 430 E+ bottoms fraction.

6. In a process for the preparation of a hydrocracking feed and theproduction of a high value coke, the steps which comprise passing aliquid hydrocarbon boiling above about 200 F. into a deasphalting anddemetalization Zone, passing HF into said zone and contacting the saidHF and said hydrocarbon for a period of 1-90 minutes therebyprecipitating substantially all the metals from the said hydrocarbon andforming an extract phase which amounts to about %-20% of said liquidhydrocarbon feed in which are concentrated .the compounds containingsulfur, nitrogen and Conradson carbon and a raffinate phase whichamounts to about 80-90% of said liquid hydrocarbon feed, saidprecipitate being collected in said extract phase, leaving a virtuallymetal-free raffinate phase, separating said extract phase and the saidrainate phase, removing the said extract phase from the saiddeasphalting zone, filtering said extract phase to remove precipitatecontaining heavy metal contaminants, passing (the filtered extract phaseinto a thermal cracking zone, said zone being maintained at atemperature of 1800- 2600 F., whereby the said metal-free extract iscracked substantially completely to a metal-free coke and hydrogen,passing at least part of the said hydrogen into a hydrocracking zone,recovering said metal-free coke as product, fractionating the saidraffinate phase into a plurality of streams including (1) a lighterboiling stream which is passed to the said hydroforming zone where it ishydroformed in the presence of hydrogen gas, recycling at least a partof said hydrogen gas from said hydroforrning Zone to the saidhydrocracking zone, (2) an intermediate stream which is removed from thesystem and (3) a bottoms stream which is passed into the saidhydrocracking zone where it is hydrocracked in the presence of therecycle hydrogen from the said hydroforming zone and hydrogen from saidthermal cracking step, recovering a low boiling hydrocrackate fractionwhich is removed from the system and a higher boiling naphtha fractionwhich is passed to the said hydroforming zone, and recovering a highquality mot-or fuel from said hydroforming Zone.

7. The process of claim 6 Where the said liquid hydrocarbon is a 950F.-|- vacuum resid. which has been diluted `with 1 to 6 volumes of a C3to C5 hydrocarbon diluent per volume of oil feed.

8. The process of claim 6 wherein the said liquid hydrocarbon is a 950F.|- vacuum resid. which has been diluted with a hydrocarbon selectedfrom the group consisting of propane, butane and pentane.

References Cited by the Examiner UNITED STATES PATENTS 2,643,971 6/1953Lien et al 208-86 2,727,853 12/1955 Hennig 208-86 2,971,905 2/1961Bieber et al. 208-252 2,973,313 2/1961 Pevere et al. 208-86 3,061,5391-0/1962 Moritz et al. 208-90 DELBERT E. GANTZ, Primary Examiner.

I. R. LIBERMAN, Examiner.

H. LEVINE, Assistant Examiner.

1. IN A PROCESS FOR THE PREPARATION OF A HYDROCRACKING FEED ANDPRODUCTION OF A HIGH VALUE COKE, THE STEPS WHICH COMPRISE PREFLASHING ACRUDE OIL, THEREBY OBTAINING A LIGHTER FRACTION BOILING BELOW ABOUT200*F. AND A HEAVIER FRACTION BOILING ABOVE ABOUT 200*F., RECOVERING THESAID LIGHTER FRACTION, PASSING SAID HEAVIER FRACTION INTO A DEASPHALTINGAND DEMETALIZIATION ZONE PASSING HF INTO SAID ZONE FOR CONTACTING SAIDHEAVIER FRACTION AND IN A SUFFICIENT AMOUNT TO PRECIPITATE SUBSTANTIALLYALL METAL FROM SAID HEAVIER FRACTION AND TO FORM AND EXTRACT PHASE WHICHAMOUNTS TO ABOUT 10-20% OF SAID CRUDE OIL FEED IN WHICH ARE CONCENTRATEDTHE COMPOUNDS CONTAINING SULFUR, NITROGEN AND CONRADSON CARBON AND ASEPARATE RAFFINATE PHASE WHICH AMOUNTS TO ABOUT 80-90% OF SAID CRUDE OILFEED, SAID PRECIPITATE BEING COLLECTED PRIMARILY IN SAID EXTRACT PHASE,SEPARATING SAID EXTRACT PHASE AND SAID RAFFINATE PHASE, REMOVING SAIDEXTRACT PHASE FROM THE SAID DEASPHALTING ZONE, FILTERING SAID EXTRACTPHASE TO REMOVE SAID PRECIPITATE CONTAINING HEAVY METAL CONTAMINANTS,PASSING THE FILTER EXTRACT PHASE INTO A HIGH TEMPERATURE THERMALCRACKING ZONE, CRACKING THE SAID METAL-FREE EXTRACT SUBSTANIALLYCOMPLETELY TO METAL-FREE COKE AND HYDROGEN, RECOVERING SAID COKE AS APREMIUM LOW METALS COKE, PASSING AT LEAST PART OF THE SAID HYDROGEN INTOA HYDROCRACKING ZONE, FRACTIONATING SAID RAFFINATE PHASE INTO THREESTREAMS, INCLUDING (1) A LIGHTER BOILING STREAM WHICH IS PASSED WITHOUTHYDROFORMING TO A HYDROFORMING ZONE WHERE IT IS HYDROFORMED IN THEPRESENCE OF HYDROGEN GAS, RECYCLING PART OF SAID HYDROGEN GAS FROM SAIDHYDROFORMING ZONE TO SAID HYDROCRACKING ZONE, (2) AN INTERMEDIATE STREAMWHICH IS REMOVED FROM THE SYSTEM AS PRODUCT, AND (3) A BOTTOMS STREAMWHICH IS PASSED WITHOUT HYDROFINING INTO THE SAID HYDROCRACKING ZONECONTAINING A CATALYST COMPRISING PALLADIUM ON AN ALUMINUM SILICATEMOLECULAR SIEVE WHERE IT IS HYDROCRACKED IN THE PRESENCE OF THE RECYCLEHYDROGEN FROM THE SAID HYDROFORMING ZONE AND HYDROGEN FROM SAID THERMALCRACKING STEP, RECOVERING A LOW BOILING HYDROCRACKATE NAPHTHA FRACTIONWHICH IS REMOVED FROM THE SYSTEM AND A HIGHER BOILING HYDROCRACKATENAPHATHA FRACTION WHICH IS PASSED TO SAID HYDROFORMING ZONE, ANDRECOVERING A HIGH QUALITY FUEL FROM THE SAID HYDROFORMING ZONE.